The present invention refers to a portable pump for infusing liquid substances into the body of a living being, particularly for infusing drugs into the body of a human being. The invention further relates to a reservoir for use in the pump, particularly an interchangeable reservoir adapted to contain a drug to be infused through the pump.
As known, the infusion of drugs in liquid form into the body of a living being such as a human being or an animal, can be effected by using electromechanical devices also known as drug infusion pumps. Such pumps can be hospital-type pumps, i.e. intended for stationary use, or they can be portable-type pumps, i.e. intended for being worn by human beings, for instance with the aid of a pouch attached to the body by means of a strap or the like. Portable-type pumps, for obvious reasons, have light weight and require a small amount of space and they further have to meet special requirements, mainly determined by their use conditions, which may vary even widely from one user to another. In this respect, one should consider that portable pumps for drug infusion are usually worn throughout the day and therefore during all the activities typically carried out by a living being, including for instance those related to personal care. Water-tightness, or at least the capacity to operate also in humid environments, for instance in the presence of mist or vapor, is therefore one of the requirements to be preferably met by a portable pump. For this reason, portable-type pumps usually comprise a casing as watertight as possible, which houses the mechanical members and the electric and electronic circuitry controlling operation of the pump and, in some kinds of pumps, also the interchangeable reservoir from which the drug is delivered. An opening provided in the casing allows the passage of a duct through which the drug exiting the reservoir by effect of the thrust imparted by the mechanical members is supplied to the living being's body.
WO 2004/084976 A1 describes an example of a portable pump of the aforementioned type comprising a casing in which a housing is defined for a drug-charged interchangeable vial, said housing having an aperture for inserting the vial and a threaded ferrule which is screwed on a threaded appendix of the casing in order to firmly lock the vial in the housing. The threaded ferrule has a hole for the passage of the duct through which the drug is delivered.
In other types of pumps, the reservoir is located outside the casing containing the pump organs and is attached to the casing by means of mechanical connections of various kinds, which, however, makes it less feasible to obtain a watertight configuration of the pump. EP 1078643 describes a further example of a portable device for drug infusion of this second known type.
The described portable pumps of the first known type, though guaranteeing good humidity-tightness, are not easy to handle, especially by patients who have difficulties in coordinating movements of their hands, as they require insertion of the reservoir in its correct position into the corresponding housing and locking of the reservoir by means of a separate ferrule to be screwed or in case fitted onto the casing. Furthermore, the reservoir, when filled and inserted in its housing provided in the pump, is usually already connected to the cannula for outflow of the drug to the patient and in this case it is obvious that in order to place the ferrule and insert it and screw it onto the pump it will be necessary to temporarily disconnect the cannula from the reservoir, in order to let it pass through the ferrule, with the risk of jeopardizing the sterility of the duct once the duct is connected to the reservoir again. In addition, the ferrule is often difficult to be inserted and screwed and can get lost easily, with consequent impossibility to proceed with the infusion of the drug.